Bale wrappers are commonly used in agriculture to wrap bales with films consisting of impervious material such as plastics to envelop the baled material in an airtight manner for the process of ensilage of fodder.
In certain embodiments, such wrappers are realized as independent machines connected to a tractor for transporting either the wrapper to the respective bales lying in the field or for transporting the bales to the wrapper (EP 0 829 197 A, GB 2 159 489 A, GB 2 305 648 A, IT 1 225 741 B, EP 0 367 529 A, WO 99/64297 A). In these wrappers, the plastic material is wrapped by rotating the bale around its horizontal axis, while either a table supporting the bale (GB 2 159 489 A, IT 1 225 741 B, EP 0 367 529 A) or an arm carrying the wrapping material (EP 0 829 197 A) is rotated simultaneously around a vertical axis, or all three rotations are commonly performed (WO 99/64297 A). The bale is released to the ground after completion of the wrapping process by tilting the table or the parts of the wrapper holding the table. The bale thus rolls down from the table to the ground. If it is intended to deposit the bale on its flat end, an auxiliary tipping device can be used behind the wrapper (GB 2 305 648 A, EP 0 910 941 A). One disadvantage of the separate wrappers is that a tractor and an operator are required for a second operation in the field after baling, and that a considerable amount of time can pass before the bale is wrapped, such that the crop may wilt or spoil in the meantime.
In other embodiments, the wrapper is mounted on a common frame with a baler (DE 41 20 733 A, EP 0 865 723 A, EP 1 186 225 A, EP 1 438 889 A) or mounted on a separate wheeled chassis that is pulled behind the baler (FR 2 658 985 A, WO 96/12399 A, U.S. Pat. No. 4,685,270 A), such that baling and wrapping can be performed in a single pass over a field and the bale is wrapped immediately after baling.
In the baler/wrapper combinations with a single frame, a table is typically provided that slides along the frame to receive the completed bale from the baler and to move it rearwards to the wrapper (DE 41 20 733 A, EP 0 865 723 A, EP 1 186 225 A, EP 1 438 889 A), or a tiltable device catches the bale from the baler and conveys it to the wrapping table (DE 41 38 499 A). The table comprises rolls or belts for rotating the bale around its axis during wrapping, while an arm carrying the wrapping material is rotated simultaneously around a vertical axis. The bale is discharged by tilting the table to the rear, such that the bale rolls down to the ground. If the bale is to be deposited on its end, a tilting device can be used behind the table for tipping the bale over (DE 41 38 499 A).
The wrappers that are pulled behind the baler are mounted on a separate chassis with two wheels that are connected to the frame of the wheeled baler by an extendable bar, which is mounted pivotally around a vertical axis to the baler frame (FR 2 658 985 A, WO 96/12399 A, U.S. Pat. No. 4,685,270 A), or by two extendable bars on both sides, while the wrapper wheels are free to rotate around a vertical axis (FR 2 658 985 A). In the contracted position of the extendable bar, a picking device of the wrapper is positioned immediately behind the outlet of the baler to receive the bale. Then the bar is extended, the bale is transported from the picking device to the wrapping table, and the bale is wrapped, by rotating the bale around its axis and an arm dispensing the wrapping material around a vertical axis, or by rotating the bale around its axis and a vertical axis (FR 2 658 985 A). Finally, the bale is deposited on the ground in the manner described with respect to the baler/wrapper combinations with a single frame.
EP 1 832 157 A proposes a baler, wrapper or baler/wrapper combination with a bale depositing device behind the baler or wrapper that can put the bale on its flat end dependent on the slope of the field.
One disadvantage of the wrapper pulled behind the baler is that the entire combination is relatively long and thus difficult to operate in a field, especially during turning in the headland and in particular when heading backwards. Another problem, both with the known wrappers pulled behind the baler and the baler/wrapper combinations having a single frame, is that if the bale is to be deposited on its flat end, additional tilting devices need to be employed for tipping the bale over during unloading, adding complexity and cost to the machine.